From: NeilBrown <neilb@suse.de>
To: Ian Pilcher <arequipeno@gmail.com>
Cc: linux-raid@vger.kernel.org
Subject: Re: Inoperative array shown as "active"
Date: Sat, 14 Sep 2013 15:59:12 +1000 [thread overview]
Message-ID: <20130914155912.5ba135d9@notabene.brown> (raw)
In-Reply-To: <l10sq0$e24$1@ger.gmane.org>
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On Sat, 14 Sep 2013 00:39:20 -0500 Ian Pilcher <arequipeno@gmail.com> wrote:
> I'm in the process of writing a program to monitor various aspects of
> my NAS. As part of this effort, I've been simulating RAID disk failures
> in a VM, and I noticed something that seems very odd.
>
> Namely, when a sufficient number of disks has been removed from a RAID-5
> or RAID-6 array to make it inoperable, the array is still shown as
> "active" in /proc/mdstat and "clean" in the sysfs array_state file. For
> example:
>
> md0 : active raid5 sde[3](F) sdd[2] sdc[1](F) sdb[0]
> 6286848 blocks super 1.2 level 5, 512k chunk, algorithm 2 [4/2] [U_U_]
>
> (mdadm does show the state as "clean, FAILED".)
>
> Is this the expected behavior?
Yes.
>
> AFAICT, this means that there is no single item in either /proc/mdstat
> or sysfs that indicates that an array such as the example above has
> failed. My program will have to parse the RAID level, calculated the
> number of failed members (if any), and determine whether that RAID level
> can survive that number of failures. Is this correct?
Yes.
>
> Anything I'm missing?
mdadm already does this for you. "mdadm --detail /dev/md0".
NeilBrown
>
> Thanks!
>
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next prev parent reply other threads:[~2013-09-14 5:59 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-14 5:39 Inoperative array shown as "active" Ian Pilcher
2013-09-14 5:59 ` NeilBrown [this message]
2013-09-14 6:25 ` Ian Pilcher
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